Your idea will work, but it will be awfully loud in the room! Soundproofing the room will help. You should have good ventilation-push/pull fans with airfow from behind you.
Here is an outdoor idea I have though about: a giant silencer that is rigidly mounted, and you shoot through it. A glasspack truck muffler would work, but the opening is too small. Perhaps 4 or 5 tires screwed together and filled with fiberglass or polyurethane foam, rigidly mounted in a frame. The more tires the quieter it will be.
Last edited by Bill DeShivs; March 17, 2007 at 02:24 AM.